I would like my iphone 6s to alert me when I have a text while wearing my apple watch 3

The way things are designed to work is, if the phone is locked, you get notifications on the watch.

You can try turning off Wrist Detection in the Watch app on your phone. Of course, this will mean that you'll need to enter a passcode to do more than look at the face of your watch. You also won't be able to use Apple Pay from your watch.